Pseudalpheopsis guana gen. nov. (Crustacea: Decapoda), sp. nov., a new alpheid shrimp from the British Virgin Islands, Caribbean Sea. Zoological Studies 46(4): 428-440. Pseudalpheopsis guana gen. nov., sp. nov. is described on the basis of a single male specimen collected from an artificial reef matrix structure (ARMS) off Guana I., British Virgin Is., Caribbean Sea. Pseudalpheopsis, gen. nov. appears to be most closely related to Alpheopsis Couti6re, 1896 (sensu lato), but differs from all species currently placed in this genus by the unique armature of the chelipeds and the presence of a "pseudo-hepatic tooth" on the anterior margin of the carapace, above the pterygostornial angle.